RF Directional Coupler

An RF directional coupler is a passive microwave device that uses electromagnetic coupling to achieve directional sampling of signal power. Its core structure consists of a transmission line and a coupling line. When a high-frequency signal propagates along the main transmission line, the coupling port extracts a specific proportion of the forward or reverse power (e.g., 10dB or 20dB coupling) while maintaining low insertion loss in the main channel (typically <0.5dB).

 

1. What are the Key Performance Parameters of RF Directional Coupler?

Coupling Coefficient: Represents the ratio of output port power to input port power, with common specifications ranging from 3dB to 30dB.

Directivity: Measures the ability to isolate forward and backward waves, with high-end products achieving over 25dB.

Bandwidth: Covers DC to 40 GHz, with multi-band design (e.g., S-band, Ka-band).

Standing Wave Ratio (VSWR): Main port VSWR ≤ 1.2:1 for high-quality devices.

 

2. What are the Typical Application Scenarios of RF Directional Coupler?

Base station power monitoring and feedback control;

RF system impedance matching diagnosis;

Phased array antenna beamforming calibration;

Microwave link fault location.

 

3. Selection Recommendations for RF Directional Coupler

Consider the operating frequency, power handling (e.g., 50W CW), ambient temperature range (-55°C to 125°C), and packaging type (surface mount/waveguide). Modern integrated designs support multi-coupling point structures, enabling simultaneous monitoring of signals in multiple frequency bands.